The invention relates to an air-conditioning system for a cab of a commercial vehicle. The air-conditioning system can supply individual areas of the cab interior with air and provides separate temperature control for controlling the temperature of the air supplied to each individual area. The invention further relates to the use of a multi-zone air-conditioning system with the individual temperature control for controlling the temperature of air supplied to individual areas of the interior of a commercial vehicle, e.g., a semi-tractor.
The cab of a relatively large commercial vehicle has a driver""s area, a front-passenger""s area and a sleeping area. In order to air condition these areas, air-conditioning systems are known which have a central control unit in the dashboard. The control unit controls the temperature of the air and supplies the air from the dashboard to, at least, the driver""s and front-passenger""s area via air ducts. The sleeping area is thereby air-conditioned at the same time. An auxiliary motor is provided to drive the compressor of the air-conditioning system as well as the fan for the parking air-conditioning system. The parking air-conditioning system functions whether or not the vehicle is moving and is desirable when sleeping overnight in the vehicle, particularly in hot climates. One disadvantage of this design is that the entire cab is cooled while the parking air-conditioning system is running.
DE 196 45 178 A1 discloses a commercial-vehicle air-conditioning system having, for a parking air-conditioning system, an ice storage device arranged in a rear wall of the sleeping area. This air-conditioning system is relatively complicated, since, in addition to the known control unit in the dashboard, it also has a second coolant circuit to which two further evaporators in the rear wall and in the roof are connected. Coolant lines are therefore laid essentially through the entire cab. These coolant lines can be associated with corresponding installation expenses and problems, such as the imperviousness of the lines to leaks etc.
Furthermore, air-conditioning systems have been developed for passenger vehicles. These systems have a central control unit which is arranged in the dashboard and in which at least one evaporator and one heating unit are arranged. A system of this type is disclosed, for example, in DE 197 39 578 A1. The air-conditioning system described therein has a downstream (air-side) temperature control. The space downstream of a heater, in which cold air which has bypassed the heater can be mixed with warm air, is divided into four air-mixing spaces which lie one next to another and are separated by partitions. The partitions extend beneath the heater and divide the cold-air bypass likewise into four sub-ducts. Via warm-air flaps, which are arranged directly downstream of the heater, and cold-air flaps, which close the cold-air bypasses, an individual temperature can be set in each mixing space irrespective of the temperatures in the other mixing spaces by mixing the cold air with the warm air according to desired levels. The air from the individual air-mixing spaces, in each of which the temperature is individually controlled, can be supplied via air ducts to the corresponding air-conditioning zones. In the process, the air is conveyed by a central fan, and the strength of the individual air streams is controlled by air flaps.
Accordingly, some objectives of the invention are to provide an improved air-conditioning system for a cab of a commercial vehicle, which is constructed as simply and cost-effectively as possible and which permits more economical air-conditioning of the individual areas of the cab interior. Another objective is to provide an improved method of air-conditioning the cab of a commercial vehicle.
In accomplishing the objects of the invention, there has been provided, according to one aspect of the invention, an air-conditioning system for a commercial vehicle cab, wherein the cab comprises in its interior a driver""s area, a front passenger""s area and a sleeping area, where the air-conditioning system comprises: (a) a central unit for separately controlling the temperature of air guided to be supplied to each interior area; (b) air ducts for guiding air from the central unit to each of the areas; and (c) a compressor in operable connection with the central unit, wherein the central unit comprises an air guiding housing including: (i) a first fan for directing air to the driver""s and front passenger""s areas via the air ducts; (ii) at least one second fan for directing air via the air ducts to the sleeping area; (ii) at least one heater in operable connection with the air ducts; and (iii) at least one cooling heat exchanger in operable connection with the air ducts.
According to another aspect of the present invention, there is provided a method for air-conditioning a commercial vehicle cab, wherein the cab comprises in its interior a driver""s area, a front passenger""s area and a sleeping area, the method comprising: (a) providing air ducts for guiding air to each of the areas; (b) providing a central unit for guiding air from the central assembly to each respective area via the air ducts and for controlling, independently the temperature of air guided to each area; (c) providing a first fan; (d) directing air with the first fan to the driver""s and front passenger""s areas via the air ducts; (e) providing at least one second fan; (f) directing air with the second fan to the sleeping area via the air ducts; (g) providing a heat exchanger in operable connection with the air ducts; (h) providing a cooling heat exchanger in operable connection with the air ducts; (i) providing refrigerant lines; and 0) providing a compressor in operable connection with the central assembly via the refrigerant lines.
Further objects, features and advantages of the invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying drawings.
The invention is explained in detail below with reference to exemplary embodiments and with reference to the accompanying drawings, in which:
FIG. 1 depicts a cab of a commercial vehicle having an air-conditioning system according to the invention according to a first preferred exemplary embodiment;
FIG. 2 shows a schematic illustration of part of the cab from FIG. 1 seen from the side;
FIG. 3 shows a schematic illustration of part of the cab from FIG. 1 see from above; and
FIG. 4 depicts a further embodiment of the air-conditioning system according to the invention.